This invention relates to circuit breaker mounting assemblies, and more particularly to such mounting assemblies having an auxiliary terminal block for connection to the auxiliary wiring of a circuit breaker.
Circuit breakers are generally used to protect electrical circuitry from damage due to an overcurrent condition, such as an overload fault or a relatively high level short circuit condition. Molded case circuit breakers, for example, include at least one pair of separable contacts which may be operated either manually by way of a handle disposed on the outside of the case or automatically in response to an overcurrent condition. In the automatic mode of operation, an electronic trip unit, for example, controls an operating mechanism that opens the separable contacts. In the manual mode of operation, the handle cooperates with the operating mechanism in order to open the separable contacts. Circuit breakers have at least one line terminal for connection to a power source and at least one load terminal for connection to a load, such as a motor. The separable contacts of the circuit breakers are internally connected to the line and load terminals. Circuit breakers may also have one or more auxiliary terminals. Such auxiliary terminals may be utilized as inputs to provide an external signal for tripping the circuit breaker. Furthermore, other such auxiliary terminals may be utilized as outputs to externally indicate the trip status of the circuit breaker. Input auxiliary terminals may include, for example, connections to a shunt trip mechanism or an undervoltage trip relay which trips the circuit breaker whenever the line voltage falls below a predetermined value.
An external auxiliary terminal block can be utilized to provide terminals for connection of the circuit breaker with such external trip mechanisms. Output auxiliary terminals may include, for example, connections to a bell alarm and other external circuits for enunciating or monitoring the open/closed/tripped status of the circuit breaker. An external auxiliary terminal block can also be utilized to provide terminals for interconnection of two circuit breaker status relay contacts having a common reference node with such external status monitoring circuits. Combinations of input and output auxiliary terminals may be provided by auxiliary terminal blocks having plural (e.g., six, nine, etc.) terminals. Circuit breakers having auxiliary terminal blocks are shown in U.S. Pat. Nos. 5,483,213 and 5,652,698.
When circuit breakers are mounted in cabinets or panelboards, the auxiliary terminal blocks shown in the above patents may not be readily accessible. There is a need, therefore, for a circuit breaker assembly having an auxiliary terminal block that improves the accessibility for connection to the internal wiring of the circuit breaker.